METHOD FOR DESULPHURIZATION AND FINAL DEDUSTING OF BOILER FLUE GAS AND AN INSTALLATION FOR DESULPHURIZATION AND FINAL DEDUSTING OF BOILER FLUE GAS

摘要

1. A method for the desulphurisation and final dedusting of combustion gases, in which the stream of gases already dedusted to the dust concentration of 0.5g/m3 is passed in counter-current through the stream of the circulating suspension of alkaline compounds, and the purified combustion gases are heated and released into air and the non-precipitated reaction products with the non-reactioned sorbent, in the form of a suspended matter, is directed to the water separation process, and water is then re-circulated, characterized in that the desulphurisation and final dedusting are carried out in two stages: in the first stage, the speed of combustion gas stream at a temperature between 120 and 200 degrees C, which was earlier dedusted to reach the concentration of dust of 0.05g/m3 is decreased from 12-25 m/s to 4-10 m/s, and further the stream is surface-cooled to a temperature below the dew point of sulphuric acid and later it is surface- and mixing-cooled by means of a water injection to a temperature of 50-90 degrees C, and further the combustion gases are separated from the acidified water, and in the second stage, the stream of combustion gases is passed through the circulating suspension of alkaline compounds, and then the drops of water are removed from it, and next ther combustuon gases are heated to a temperature of combustion gas convection in a stack, and the separated acidified water is entered into the circulation of alkaline compounds suspension.3. A device for the desulphurisation and final dedusting of combustion gases generally dedusted in a standard dedusting device, contains a scrubber supplied with an alkaline compounds suspension, characterized in that an exchanger is placed in front of the scrubber (8).IMAGE